I have discovered that my gr-gr-grandfather James Heap (b. c1827, Plymouth, Devon) had a brother William (b c1825, Portsmouth, Hants) who emigrated to the USA with his wife Mary in the 1850s, settling in New Hampshire. They had six girls and a boy.
The youngest of the girls, Olive (b c 1870), married a John M. Cox (b c1867, NH)and to the best of my knowledge they had no children. The 1900-30 US censuses show them living in Laconia NH.

Does this ring a bell with anyone?
Malcolm Choat